Conventional combustion, reciprocating engines are widely used as automotive engines. A conventional engine (single-cycle, two-cycle and others) is typically composed of an engine or cylinder assembly having one or more cylinders therein. A piston is slidably disposed in the cylinder and moves reciprocally within the cylinder. A cylinder head at one end of the cylinder completes the cylinder assembly. The cylinder head typically contains the valves (intake and exhaust) and the spark plug. The spark plug typically ignites a pre-mixed fuel that is injected by the intake valve into a combustion chamber and helps to define an ignition event.
Should an ignition event not occur or the cylinder misfires, it can reduce the power output of the engine, can cause low fuel economy and poor performance. Additionally, if the misfire of the cylinder continues for an extended period of time, the cylinder and/or the engine may be permanently damaged. Engine analyzers are used to analyze the performance of internal combustion engines. Engine tests can include tests, such as ignition events of a cylinder, detection of rotation-per-minute fluctuations of engine input, exhaust pipe temperature changes, relative temperature differences among the exhaust ports, rotational torque variations, exhaust pressure pulsing, and abnormal content of exhaust gases.
A conventional digital analyzer can convert analog signals to digital signals for display on an oscilloscope. The oscilloscope can display snapshots of discrete portions of the signals as waveforms. In the case of multiple cylinders, waveforms showing the primary and the secondary ignition voltages are displayed on the analyzer. The voltages are acquired from a primary and a secondary lead that are connected to an ignition coil. A synch probe may be attached to the first cylinder so that the analyzer can identify the cylinders (by knowing where in the sequence the first cylinder is) and determine the firing order of the cylinders. The analyzer can display sweeps, such as an engine sweep or a fixed time sweep. Engine sweeps can display a single cylinder ignition event or a complete cycle of ignition events. Additionally, the engine sweep may be displayed as cylinder, parade, or raster view. Cylinder sweep displays only a single cylinder waveform while the parade and raster display all the cylinders but in a horizontal progression or stacked vertically on top of one another, respectively. The fixed time sweep displays a fixed period of time in which the data is to be collected and shown as determined by a user.
In secondary ignition voltage, the voltage displayed from an ignition pulse typically has a spike portion, a square portion and a residual energy portion. The data from the spike portion can occur rapidly and conventional analyzer do not show the real data spike, rather an average of the spike, thus can provide an operator with false data. With false data, the operator can incorrectly diagnose or miss the misfire of a cylinder, thereby delaying the repairs and increasing costs to the consumer.
Therefore, there is a need for an apparatus and a method to display the data of an ignition event more accurately.